Hi, there is already a small pin size hole on every unit. This is just plug an play and there is no need to poke a hole unless they customer cannot smell anything after few days of use and they see the filter has absolutely no water inside the tube after few days of use.

Poking a hole bigger than its already pin size hole will make the filter finish very very fast. It just plug and play without any poking of holes by user, it will last 2-3 mths per stick.

Hi, this is designed for use with hot water. Not to worry, this product is sold in singapore for over 6 years with thousands of customers as young as new borns. It is food grade vitamin c (80%), with natural essential oil for aroma (20%).